Apparatus for controlling the temperature of the human body



y 16, 1968 D. R. BURTON 3,392,545

APPARATUS FOR CONTROLLING THE TEMPERATURE OF THE HUMAN BODY Original Filed March 27, 1964 2 Sheets-Sheet 1 j flew eA' Foo 06y .BuflfO/i 7 INVEN TOR TTORNE Y5 Ch U COOL/N6 July 16, 1968 D. R. BURTON 3,

APPARATUS FOR CONTROLLING THE TEMPERATURE OF THE HUMAN BODY Original Filed March 27, 1964 2 Sheets-Sheet :1:

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J 33- r //7 i W ,0 flare/4 Fad/26y fiarfo/l INVEN TOR w MWL United States Patent 3,392,545 APPARATUS FOR CONTROLLING THE TEMPERA- TURE OF THE HUMAN BODY Derek Rodney Burton, Farnborough, England, assignor to Minister of Aviation in Her Majestys Government of the United Kingdom of Great Britain, and Northern Ireland, London, England Original application Mar. 27, 1964, Ser. No. 355,390, now Patent No. 3,316,732. Divided and this application Jan. 20, 1967, Ser. No. 619,112

6 Claims. (Cl. 62-459) ABSTRACT OF THE DISCLOSURE An apparatus for controlling temperature of the human body comprising a garment having a circuit of liquid carrying pipes attached on the inner wall thereof. The pipes are connected so that liquid will flow in the same sense in relation to the central region of the trunk. The liquid carried by the pipes is circulated through a chamber of crushing melting ice with the amount of liquid passing through and the degree of cooling being governed by a three-way valve. The valve passes a part of the liquid through the ice chamber and bypasses a part thereof to maintain a mixed output of bypassed liquid and liquid passing through the chamber at a predetermined temperature for delivery to the pipe circuit. The valve may be thermostatically controlled.

This application is a division of patent application Ser. No. 355,390, now Patent No. 3,316,732, filed Mar. 27, 1964.

This invention relates to apparatus for controlling the temperature of the human body by means which cool the skin. An example of such systems is a ventilated pressure suit as is worn by an aviator which, conventionally, includes means for distributing a flow of cooling and ventilating air over the body of the wearer and exhausting it from the suit. The temperature and flow rate of the air are adjusted to provide the conditions the wearer requires.

A disadvantage of the known apparatus in which air is the cooling fluid is that because of its low density and low specific heat large volumes of air are required to obtain the necessary conditions. Consequently a relatively large amount of power is required to circulate the air.

According to the present invention, apparatus for controlling the temperature of the human body comprises a garment worn on the body and a system of liquid carrying pipes positioned inside the garment to come in contact with the skin, the pipes running generally from the extremities towards the centre of the body in the region of the abdomen, together with a first manifold connected to the open ends of the pipes at the extremities of the body and a second manifold connected with the opposite open ends of the pipes at the centre of the body, the manifolds being connected through means for circulating the cooling liquid in a circuit including the manifolds, the pipes and a heat exchanger in which its temperature is adjusted.

Preferably the apparatus is so adopted that, when it is used for cooling, the liquid flown from the extremities of the body towards the centre, that is to say from the cooler parts of the body towards those which are warmer whereby, as the liquid flows to progressively warmer parts a small and relatively constant temperature diflerential will be maintained between the liquid and the body temperatures.

Advantageously and preferably the cooling liquid is water.

In one form of the apparatus which is to be used for cooling, the cooling liquid is circulated through a chamber full of crushed melting ice the amount passing through and the degree of cooling being governed by a three-way valve which by-passes a proportion of the cooling water only through the crushed ice chamber as is necessary to maintain a mixed output at a predetermined temperature, the mixed output consisting in part of liquid which has passed through the chamber and in part of liquid which has been supplied directly from the three-way valve. The period of operation for this form of cooler will depend on the time required to melt the ice and raise the melted ice to a temperature at which it no longer has any beneficial cooling etfect. The three-way valve may be thermostatically controlled so that the amount of water or cooling liquid which it passes through the cooling chamber and by-passes is governed to maintain the mixed output from the cooling and the by-pass at the required temperature.

The invention will now be described with reference to the accompanying diagrammatic drawings in which:

FIGURE 1 is half of a pressure suit garment showing the pipework,

FIGURE 2 is a form of the apparatus using melting ice as a coolant,

FIGURE 3 gives test results of a typical cooler, and

FIGURE 4 illustrates the efliciency of one form of the apparatus.

Referring to the drawings, FIGURE 1 shows the outline 10 of one half of the pressure suit. Within the suit there is an inlet manifold 11 which is divided into two parts 11a and 11b at a junction J in the region of the centre of the suit near the abdomen of the supposed wearer. The halves of the manifold 11a and 11b lead to the extreme ends E1 and E2 of the arm and leg portions of the suit respectively. In the same central region of the suit, there is an outlet manifold 14. Within the suit the ends of the inlet manifold in the regions E1 and E2 are in fluid connection with a number of small bore flexible conductive pipes as at 15 which run from the ends E1 and E2 along the length of the extremities towards the centre portion of the suit where they are connected with the outlet manifold 14.

The apparatus is completed by a pump 16 and a cooler 17 connected in a liquid flow circuit formed by the pipes 18 and 19 as shown, whereby a continuous flow of the liquid through the small bore pipes within the suit may be maintained in the direction of the arrows A from the extremities E1 and E2 towards the centre of the suit.

A simple form of cooler suitable for use with the apparatus of FIGURE 1 is shown in FIGURE 2.

The apparatus of FIGURE 2 is a portable device including an expendable supply of coolant. The apparatus consists of a coolant chamber which is housed in an insulating jacket 81 and is, in use, filled with crushed melting ice 82. The flow and return pipes 83 and 84 conmeeting the chamber 80 with the suit 85 are connected by a by-pass 86 joined to the flow pipe 83 by a three way valve 87, the valve 87 being adjustable to vary the amount of suit cooling water flowing from the suit through the melting ice in the chamber 80. The flow through the chamber 80 is adjusted to control the mixed outlet water temperature leaving the bypass junction 88 at the required value. For this purpose, the three-way valve 87 may also be thermostatically controlled to maintain the mixed output from the cooling chamber and the by-pass at the required temperature. The period of operation of this form of cooler will depend on the time required to melt the ice and raise the melted ice to a temperature at which it no longer has beneficial cooling effect.

FIGURE 3 is a series of graphs showing test results achieved by a simple cooler in FIGURE 2 at different tap settings. The ordinate scale represents the centigrade heat unit measurement of the cooling effect and the abscissa the time scale in minutes. The curves A and B represent typical comfort levels in ditferent circumstances as may be experienced by an aviator, curve A indicating a heat loss of 500 B.t.u.s per hour and curve B a loss of 413 B.t.u.s per hour. Curves I, II and III show the results achieved and it will be seen that the comfort range is well within the range of performance of the apparatus.

FIGURE 3 is a graph showing the efliciency of a suit similar to that of FIGURE 1 in terms of temperature drop achieved in relation to an ideal temperature assuming, as is usual, a skin temperature of 33 C. The figures apply, of course, to a suit of particular characteristics. In this case the cooling system consisted of ten small bore pipes, internal diameter 1.5 mm. connected with manifolds of internal diameter 4.0 mm. It will be understood of course, that another suit having different pipe sizes and water capacity etc. would have a different performance. The ordinate of the graph is the efliciency E, in terms of out' in Era-Ti.

AP pg1rD4 m is the flow of cooling water in lb./hr. per tube, 1 is the length of the tube, in feet,

,u. the viscosity of water in lb./ ft. hr.,

p the density of water in lb./ft.

g an acceleration constant in ft./hr., and

D is the tube diameter in feet.

In designing a suit to fulfill a particular requirement the sequence of design steps is to determine a the heat loss requirements of the wearer, b the weight of water required, c the pressure drop across the small bore pipe system, measuring inlet and outlet pressures in the manifolds, and d the choice of pipe arrangement and pump applying the above formula. It will be obvious that the manifolds themselves and the connections of the small bore pipes with them must be such as to cause as little pressure drop as possible so that calculations can be based primarily on the characteristics of the small bore pipes.

Generally speaking, the various types of apparatus described in the foregoing have a limited working life determined in some cases by the capacity of the suit pipe system and in others by the initial capacity of the refrigerant reservoir or coolant liquid. It will be understood, however, that the period of operation of the suit or apparatus is generally determined solely by the capacity or supply of coolant.

The advantages of the liquid, particularly water-cooled, apparatus of the invention compared with air-cooled apparatus for the same duty include an enormous reduction of pumping power of the coolant by as much as 3300 times. This permits the operation of the apparatus as smaller temperature differences between the skin and the coolant and hence a reduction of the insulation between the coolant pipes and the skin.

I claim:

1. Apparatus for controlling the temperature of a human body comprising a garment consisting of trunk, leg and arm portions, and a liquid circuit including a system of liquid carrying pipes so attached to the garment that at least a proportion of the exposed inner face of the garment which will contact the body of a wearer of the garment is formed of exposed pipe wall, the pipes running generally outwardly from the central region of the trunk portion, manifold means in the central region connected with an end of each pipe, manifold means at the extremities of the leg and arm portions and connected with the other ends of the pipes, the circuit being completed by a conduit system independent of the pipes and connecting the central manifold to each of the other manifolds and including means for circulating and temperature conditioning the liquid.

2. Apparatus according to claim 1 in which the circulating liquid is water.

3. Apparatus according to claim 1 in which the solid refrigerant is ice.

4. Apparatus according to claim 1 in which the garment embodying the liquid circuit, the heat exchanger and the means for circulating the circulating liquid includes liquid passing around the liquid circuit from the extremities of the leg and arm portions to the centre of the trunk portion.

5. Apparatus for controlling the temperature of a human body comprising a garment consisting of at least a trunk portion and a liquid circuit including a system of liquid carrying pipes so attached to the garment that at least a proportion of the exposed inner face of the garment which will contact the body of a wearer of the garment is formed of exposed pipe wall, the pipes running generally outwardly from the central region of the trunk portion and so connected in the liquid circuit that liquid will flow through all the several pipes in the same sense in relation to the central region, the circuit having means whereby temperature control and circulation of the liquid is effected, said temperature control and circulation means comprising a heat exchanger operative to cool the circulating liquid, said heat exchanger including a container through which the garment circulating liquid circulates, a crushed solid refrigerant in the container in granular form with liquid passageways between the granules, the solid refrigerant being miscible with the circulating liquid whereby :the circulating liquid is cooled by direct contact of the liquid with the solid refrigerant.

6. Apparatus according to claim 5 which further includes means for by-passing a proportion of the cooling water so that only a portion flows through the crushed solid refrigerant container as is necessary to maintain a mixed output at a predetermined temperature, said mixed output consisting in part of liquid which has passed through said container and in part of liquid which has bypassed the chamber.

A References Cited UNITED STATES PATENTS 2,111,905 3/1938 Smith 62-332 2,437,332 3/1948 Newton 62332 3,000,616 9/1961 Spangler 46 3,112,792 12/1963 Coleman 16546 WILLIAM J. WYE, Primary Examiner. 

